Mesh networks go to work

Meshes are self-routing peer-to-peer wireless networks. From providing rural broadband connectivity, they are now moving into the corporate space, for campus and in-building WLAN coverage.

By
ryan Betts, Techworld
| Apr 15, 2004

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Mesh networks are the new big thing for providing wireless Ethernet coverage above the LAN level. Now, with the first deployments under their belts and providing wireless broadband to country villages, mesh suppliers want to move on and sell meshes to enterprises.

Meshes work by using the network nodes themselves to repeat data packet on to other nodes. Algorithms running on a control processor keep track of the mesh's configuration as it changes, and determine how to route packets from node to node.

The upshot is that a mesh can form a single LAN way beyond the normal range of wireless Ethernet. It also forms its own backhaul, because as long as one node is connected to the Internet, all nodes are connected.

So with a mesh in place there is no need to run fixed Ethernet to every wireless AP in the building. You simply cable up one of the access points, and the rest can share that connection over the wireless.

This kind of solution is already providing broadband access to rural communities. For example, in three Kent villages, wireless ISP Telabria has linked up with brewer Shepherd Neame to make the pub the hub of the community in more ways than one.

Each pub has a two-way 2Mbps satellite connection to the Internet, which is then shared with residents and local businesses via a mesh network. For £30 a month, subscribers get a small box, typically attached to the mast of their TV aerial, and containing two wireless Ethernet cards, one for the mesh and one as a local AP.

Jim Baker, Telabria's founder and CEO, says this means you can avoid radio congestion by having 11a or 11g as the mesh backhaul, and 11g or 11b as the WLAN. "We can get 4Mbps to 5Mbps between houses," he adds.

The next step is for schools to trial a campus-based mesh network, he says: "The mesh is still a WLAN, so it allows people to share resources such as storage, printers and cameras, all without going to the Internet."

In fact, you could even do without the access points altogether and let the PCs do their own relaying. Mesh software supplier BPO Solutions has developed and begun beta-testing a cut-down version of its Meshhopper technology specifically for Microsoft Windows.

Called MiniMesh-Pro, it creates an ad-hoc WLAN that interconnects all the meshed PCs, even if some of them are too far apart to reach each other within a normal peer-to-peer WLAN. Traffic between the distant nodes is routed by those in between.

And because there will normally be a 'cloud' of meshed nodes, there can be multiple redundant paths through the network, which provides the capability for traffic balancing.

"It is peer-to-peer in its truest sense, but for network access there has to be an admin point, and you need security to control access to the backhaul," says BPO's CTO Andrew Ramshaw.

"We say it's 'the price of a DVD' - we want to make it affordable. We can add enterprise features such as reserving bandwidth for key applications.

"The difference is the hardware cost - with Meshhopper you only have to have the wireless card and you only need to be in range of one other person. You could even embed the software in a CCTV camera and relay the signal to base."

One issue is that there is still no standard protocol for mesh networks, although some are more popular than others - Jim Baker highlights AODV for example.

For the moment though, software developers will continue to add their own tweaks. "We put in our own bits to make it more transparent to the user and more secure," says Andrew Ramshaw.

"We need to consider a lot of background things too, such as link quality and station capability - for example you don't want to rely too heavily on a node that is a laptop with a low battery. We work to Internet standards, but until this thing takes off we're looking at almost every installation being bespoke."